Award: EF-1220034

Ocean acidification (OA) is emerging as a prominent threat to the marine system, with rising atmospheric CO2 concentrations causing ocean pH to decrease at extremely rapid rates. Acidification, being a combined process of increasing CO­2 and decreasing pH has the potential to affect organismal function through multiple eco-physiological mechanisms. Early life stages are a crucial starting point to investigate the impacts of ocean acidification as young animals are the foundation of future populations, and they are often particularly susceptible to environmental changes. Squid play a major role in many marine ecosystems. They are both predators and prey for a variety of animals (dolphins, whales, seabirds, tunas) across the food web. Many squid species constitute or support productive fisheries and are thought to make up one-fifth of all global fisheries landings and values. While ocean acidification is poised to substantially impact a diverse array of marine organisms, there is little understanding of if or how decreasing pH and higher levels of CO2 may impact squid, much less their eggs and young. The goal of this work was to fill this knowledge gap by quantifying how ocean acidification conditions impacted squid embryonic and larval development, behavior, metabolism and survival, as well as address the mechanisms that potentially induce these changes. The squid species studied, Doryteuthis pealeii, is an important commercial species for Atlantic coastal fisheries and understanding these effects is vital to estimating ecosystem and economic impacts in this and other cephalopod species. Our work was the first to show that squid raised under elevated pCO2 demonstrated significant developmental changes including increased time to hatching and shorter mantle lengths, although differences were small. Their statoliths, calcium carbonate stones that are key components of an organ that is critical for balance and movement, had significantly reduced surface area and were abnormally shaped with increased porosity and altered crystal structure in elevated pCO2-reared paralarvae. These developmental and physiological effects could alter squid paralarvae behavior and survival in the wild, directly and indirectly impacting marine food webs and commercial fisheries. Despite these changes, we found some indication that these squid may be resilient to environmental changes. For example, we measured the changes in oxygen and pH adjacent to and within normally-developing squid (Doryteuthis pealeii) egg capsules, structures that house hundreds of respiring embryos. The capsules contained extremely low internal pH and near-anoxic (oxygen-deprived) oxygen concentrations. While early-stage egg capsules had pH and oxygen levels significantly lower than the surrounding seawater, late-stage capsules dropped dramatically to levels considered metabolically stressful even for adults. This suggests squid may be adapted to these ?harsh? conditions, although they may already be near their energetic limit. Yet, natural water flow-enhanced gas and chemical exchange across the physical boundary layer surrounding the egg capsules may function to alleviate these stressful intracapsular conditions. While squid may be adapted to these stressful, natural conditions, further climate change could place young, keystone squid outside of their physiological limits. Our current analyses aim to explore this potential natural resistance to environmental stressors in the early life stages of this species and their physiological limits. As part of this effort two graduate students and eight undergraduates or recent-college-graduates were involved and trained (including 3 underrepresented minorities). One student received his Masters of Science with this research and is continuing on with his PhD. Two high-school students were involved as part of their science fair project. Two videos were created to highlight the research addressed; one aired on Canadian public television, one online. We communicated these results in more than a dozen presentations, four scientific publications, with another submitted and several more in preparation. These publications, the results and several of our methods were posted online for Open Access. With these, we published press releases or public summaries, which fostered many popular online and print press articles in venues such as Discovery Channel, Time, Yahoo and Scientific American. The PhD student fostered and co-organized an exhibition of elementary school students? poems on climate-change and OA, and created an online slideshow of these works. They have also participated in several regional science festivals, presenting information on OA to the public. This projected supported the development of two graduate level courses and classes on squid biology taught to preschool children and kindergarteners. More broadly our research blog, which features this work, has over 23,000 hits from across the globe. Last Modified: 09/30/2016 Submitted by: T. Aran Mooney